Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH/RFC] New module refcounting for net_proto_family | Date | Wed, 19 Feb 2003 14:54:21 +1100 |
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In message <5.1.0.14.2.20030218101309.048d4288@mail1.qualcomm.com> you write: > At 07:46 PM 2/17/2003, David S. Miller wrote: > > >After talking to Alexey, I don't like this patch. > > > >The new module subsystem was supposed to deal with things > >like this cleanly, and this patch is merely a hack to cover > >up for it's shortcomings.
I don't quite understand.
There are some issue with this patch, however.
Firstly, the owner field should probably be in struct proto_ops not struct socket, where the function pointers are.
The sk thing looks reasonable at first glance. Getting a reference to npf->owner, then holding it for the socket is a little confusing, but an obvious optimization over a naive "get, use, drop, get".
In sys_accept:
> @@ -1196,9 +1198,13 @@ > if (!(newsock = sock_alloc())) > goto out_put; > > - newsock->type = sock->type; > - newsock->ops = sock->ops; > + newsock->type = sock->type; > + newsock->ops = sock->ops; > + newsock->owner = sock->owner; > > + try_module_get(sock->owner); > + newsock->owner = sock->owner; > + > err = sock->ops->accept(sock, newsock, sock->file->f_flags); > if (err < 0) > goto out_release;
You still need to check the result of try_module_get, and fail if it fails. The *only* time this will fail is when someone is doing an "rmmod --wait" on the module, which presumably means they really do not want you to increase the reference count furthur.
Hope that helps, Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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